A wet stain on the downstairs neighbours' ceiling, salt deposits and streaks on the facade under the balcony, tiles that come loose or sound hollow when tapped — a common picture in Tbilisi, especially on old balconies and on terraces after a renovation. The cause is almost always the same: there is no working waterproofing under the tiles.
Tiles are not waterproofing
Tiles look as if they cover the whole floor. In reality water gets through the grout: it is porous and cracks over time. Then the water soaks into the adhesive and the screed, collects there and looks for a way out — through cracks in the concrete slab, at the edge of the balcony, by the wall. That is why regrouting or smearing sealant over the joints only helps for a short while: the water already in the screed hasn't gone anywhere, and new cracks appear within a season.
Where it leaks most often
- There is no waterproofing under the tiles at all. Common on old balconies and wherever tiles were laid without a waterproofing layer.
- Where the floor meets the wall and the threshold. The waterproofing was done on the floor only and not turned up the wall or taken under the door threshold — water runs into the corner.
- No fall. Water should run from the wall towards the edge or a drain. If there is no fall or the screed has sagged, water sits under the tiles for days after rain.
- The balcony edge. If the edge has no profile or nosing for water to drip off, it runs under the concrete slab and along its underside — to the neighbours and onto the facade.
- The drain or outlet. Clogged or poorly connected to the waterproofing — water bypasses the pipe.
- Railing posts and brackets. Every fixing through the tiles is a hole that sooner or later starts letting water in.
- Thermal cracks. On a large open terrace, tiles and screed expand in the sun and contract in winter. Without movement joints, cracks appear.
Can it be fixed without lifting the tiles?
Sometimes. If the tiles are sound, there is waterproofing underneath and the water comes through one detail — a drain, a railing post, the threshold — repairing that detail is enough. This shows up at the inspection.
If there is no waterproofing under the tiles, the screed is wet or tiles are coming loose over a large area, coatings applied over the tiles give only a temporary result. Then the reliable way is to lift the tiles and redo the base.
How we do it properly
- Removal of the tiles and the old screed if it is wet, broken down or has no fall.
- A screed laid to falls from the wall towards the edge or a drain.
- Priming the base.
- Flexible waterproofing in two coats. Turned up the wall and taken under the threshold; corners and junctions reinforced with tape.
- Details done separately: drains, railing posts, and a balcony edge with a profile that lets water drip off instead of running under the slab.
- A water test before the tiles go down: we flood the terrace and check from below that it stays dry.
- Tiles on flexible adhesive. On terraces above living space we add a drainage layer under the finish where needed.
The engineer writes in the report what suits your terrace after the inspection.
If it is leaking into the neighbours' flat
Repairs downstairs only make sense once the water from above has been stopped. The engineer's written report also helps in talks with the neighbours or the homeowner association: it states where the water comes from and what needs to be done.
What to do right now
- Clear the drain or outlet and remove any water standing on the floor.
- Don't fill the joints with sealant "over the stain": it hides the place where water gets in and makes it harder to find.
- Take photos of the stain from below and of the terrace after rain — it helps the engineer.
The inspection costs 100 ₾; if you order the work from us, we deduct it from the estimate.